Southern Iberia as a refuge for the last Neanderthal populations

Abstract

Aim This paper evaluates the role of southern Iberia as a glacial refugium for Neanderthal populations during the late Pleistocene. Location Southern Iberia. Methods A new methodology employing biogeographical principles was developed to determine the nature and extent of refugial environments in southern Iberia. Two climate maps drawing on present-day temperature and rainfall measurements from 338 weather stations across the study area were constructed. The maps were then subjected to incremental falls in temperature and rainfall, and redrawn accordingly within a geographical information system (GIS) framework. The resulting cool and dry models were then combined to replicate climate conditions in southern Iberia during the last glacial period. Results The results indicated that not one but four different types of refugial environment were present: warm/wet, cool/dry, warm/dry and cool/wet. A dataset of 164 Middle Palaeolithic sites was examined with respect to these environments and shown by a chi-square test to be unevenly distributed. The overwhelming majority of sites fell within the warm/wet and cool/wet refugial environments, which shared the common characteristic of high rainfall levels. Within both these environments, it was possible to identify more specific refugia. An upland refugium was identified in the Betic Mountains in Córdoba/Jaén provinces, and a resource-rich major refugium was located on the southerly and westerly foothills of the Cádiz–Málaga sierras in an area that included the Guadalete River, two coastlines and the Rock of Gibraltar. The modelling procedure is supported by the identification within the major refugium of Gorham’s Cave in Gibraltar; archaeological evidence suggests that the cave was home to the last Neanderthals of Europe, who disappeared around 28,000 years ago. Main conclusions The persistence of good rainfall levels was a significant factor in the late survival of Neanderthal populations in southern Iberia. The potential application of the proposed climatic modelling technique to palaeobiogeography, historical biogeography and macroecology, in addition to palaeoanthropology, is considerable.